Hi
I’m hoping to get the K8400 soon.
Does anyone know if this printer can be adapted to print flexible filaments? I saw some adaptations for the K8200, but it looks like the head / nozzles have changed quite a bit since then.
K8400 has a Bowden extruder, which is not ideal for printing flexible filaments.
If i had one of these i could try to make a working fex filament modification.
But at the moment i can’t afford to by another printer.
Maybe it is possible to get a printer lended for development?
Thanks for the reply. That was my worry. Is the bowden tube made of PTFE? Maybe it’s still possible if there is additional guiding between where the filament exits the tube before entering the nozzle?
BTW the print quality looks fantastic on the new printer!
I don’t think you will get a good result with flex filament on a bowden machine.
The “tube” (bowden) has to be larger in diameter as the filament, and therefor the flex filament will expand too much in the tube, so a constant extruder rate with flex filament donsn’t seem possible…
However, it’s worth a try…
Regards
Thanks!
Yes, we use PTFE tubes.
The dimensions of the PTFE tube are 4mm outer diameter and 2mm inner diameter.
I’ve printed filaflex a few days ago and it was no big problem.
The only important thing was to print slow as fast extrusion causes in wound up filament in the extruder.
Ah, that’s great to know, thanks for the info. I’ve got a reel of it to try out so I’ll have a play with it at some point.
He’s using an E3D hot-end. It’s OK for one print head but not for 2.
Yes, but flex print or dual print… “My heart is torn between the two of them.” 
Hi !
Here another video :
youtube.com/watch?x-yt-cl=8 … uj0Qr1_K6w
E3D-V6 is one thing. But most important is that we have moved the feeder motor just above the hot-end as you can see from the video.
Thank you !
Could you post some picture of the modified parts ?
We will soon release an article to explain which parts we adapted. We will also publish stl files.
Thank you !
that will be mega
good job looks gr8
Well as a keen angler desperate to start printing soft plastic fishing lures, that looks great!
But I guess this means you couldn’t print the flexible filament using the standard set up with the bowden tube and print head?
Does the extruder add a lot of weight to the print head? I know the Vertex is built like a tank, but maybe it wasn’t designed to have all that extra weight jerking about for long prints - is it possible it could damage the printer?
I’m planning to test PolyFlex and Filaflex soon by just trying with the speed settings set really really slow… no idea if it’ll work. Fingers crossed!
I don’t think it is impossible with the standard Vertex bowden setup. This guy has done something similar: https://talpadk.wordpress.com/2013/10/10/3d-printing-using-ninja-flex-filament/. There are also some hints about how to make it work.
In the end I think it mostly depends on your needs. If you have objects to print which requires a minimum of retraction and constant pressure, I would say that the odds are good. Why not just try it out?
I don’t think it is impossible with the standard Vertex bowden setup. This guy has done something similar: https://talpadk.wordpress.com/2013/10/10/3d-printing-using-ninja-flex-filament/. There are also some hints about how to make it work.
In the end I think it mostly depends on your needs. If you have objects to print which requires a minimum of retraction and constant pressure, I would say that the odds are good. Why not just try it out?[/quote]
In fact it is possible to get something with original K8400, without modifications. As you say it depends of settings, retractation, etc
We made modifications to the extruder to be sure that ALL flexible filaments printing will be successfull.
Just an update to this in case someone comes across this old thread via the search engines. Printing filaflex is possible with the Vertex. I have successfully printed many objects now. However, it’s not easy and you have to watch your feeder / extruder for filament buckling and quickly press the release lever if you see it!
Basically, slow everything down and raise the temperature. Turn retraction and cool head lift off.
Print temp: 240C
Print speed: 15mm/s (everywhere)
Fan: 50% (though I drop to 30% during start up via the gcode)
First layer width: 80%.
Layers: 0.3mm
For my purposes, I use zero fill and the thinnest walls I can get away with (generally 0.7-0.5mm) as I need the softest, most flexible object imaginable - and even like this it’s right on the limit of working acceptably, but it can be done. I actually wish there was an even softer, more flexible filament to try but I can imagine print speeds for that would have to be practically glacial… 
The surface quality isn’t great on this print - but my later prints are looking almost blob free and rather nice.
